Definition from Wiktionary, the free dictionary
- to crush something with a noisy crackling sound, especially with reference to food
- When I came home, Susan was watching TV with her feet up on the couch, crunching a piece of celery.
- to be crushed with a noisy crackling sound.
- Beetles crunched beneath the men's heavy boots as they worked.
- (slang) to calculate or otherwise process (e.g. to crunch numbers: to perform mathematical calculations)
- That meta data makes it much easier for the search engine software to quickly crunch the data for search queries.
to crush something with a noisy crackling sound
to be crushed with a noisy crackling sound
slang: to calculate or otherwise process
crunch (plural crunches)
- A noisy crackling sound; the sound usually associated with crunching.
- A critical moment or event.
- (exercise (sport)) A form of abdominal exercise, based on a sit-up but in which the lower back remains in contact with the floor.
Derived terms 
Coordinate terms 
a noisy crackling sound
form of abdominal exercise based on a sit-up